Kawasaki Steel Corporation

Takashi Obara

Kozo Tsunoyama

Susumu Satoh

Kei Sakata

Minoru Takashima

Saiji Matsuoka

Keiji Sato

Osamu Furukimi

Hideo Suzuki

Minoru Nishida

Susumu Sato

Toshio Irie

Kaneharu Okuda

Mitsumasa Kurosawa

Yoshikazu Kawabata

Masahiko Morita

Susumu Okada

Osamu Hashimoto

Hideo Kuguminato

Yoshiaki Iida

Kazunori Osawa

Susumu Masui

Masatoshi Shinozaki

Makoto Imanaka

Atsushi Ogino

Masahiko Manabe

Hideo Kobayashi

Toshito Takamiya

Kazuhiro Seto

Kazuo Mochizuki

Masaki Kawano

Toshio Ichida

Hideo Abe

Atsuhito Honda

Takaaki Hira

Fumiya Yanagishima

Takahiro Kan

Shunichi Tsugawa

Shigeru Kobayashi

Hideo Sunami

Yoshio Yamazaki

Kazuya Miura

Fumihiko Takeuchi

Koji Yano

Kazumi Morita

Yoshinari Muro

Kouji Yano

Syusaku Takagi

Yoshio Izumiyama

Tetsuya Kiyasu

Thick cold rolled steel sheet excellent in deep drawability and method of manufacturing the same

A cold rolled steel sheet having high strength and high formability and having excellent crushing performance can include 0.05-0.40 mass % of C, 1.0-3.0 mass % of Si, 0.6-3.0 mass % of Mn, 0.02-1.5 mass % of Cr, 0.010-0.20 mass % of P and 0.01-0.3 mass % of Al, with the remainder consisting essentially of Fe. The steel sheet includes a ferrite major phase and a minor phase consisting of martensite, acicular ferrite and retained austenite. The cold rolled steel sheet can be used in automobiles.

High-strength high-workability cold rolled steel sheet having excellent impact resistance

Disclosed are bake-hardenable sheet steel with good anti-aging property and a method for producing it. While controlling its C, P, S and N contents, the chemical composition of the sheet steel is defined to comprise not larger than 1.0% of Si, not larger than 3.0% of Mn, from 0.01 to 0.20% of Al and from 0.001 to 0.2% of Ti, in terms of % by weight. The value A (&equals;(AI,&minus;AI)/AI,) of the sheet steel is defined to be not smaller than 0.4 and the value AI,thereof to be not smaller than 30; or the ratio of the mean misorientation, M (degree), to the mean grain size, G (&mgr;m), M/G, of the sheet steel is defined to be not smaller than 0.8. The steel may additionally contain from 0.001 to 0.2% of Nb and/or from 0.0001 to 0.0080% of B. While controlling its Si, Mn, S, Al and N contents, the chemical composition of a steel slab is defined to comprise from 0.005 to 0.02% of C, not larger than 0.05% of P and from 0.025 to 0.19% of Nb, with satisfying the condition of 0.7&times;(C/12)&lE;Nb/93&lE;1.2&times;(C/12) (where C indicates the C content (wt. %), and Nb indicates the Nb content (wt. %)). To produce bake-hardenable sheet steel from it, the slab is heated, hot-rolled at a finishing delivery temperature of from 960 to 650&deg; C., coiled at a temperature of from 750 to 400&deg; C., then cold-rolled to a reduction of from 50 to 95%, and thereafter annealed for recrystallization at a temperature of from 750 to 920&deg; C. The slab may additionally contain B and/or Ti. The invention stably produces bake-hardenable sheet steel on an industrial scale.

Coated seizure-hardening type cold-rolled steel sheet having excellent aging resistance and method of production thereof

Thin steel sheet having excellent rectangular drawability and production

Cold rolled steel sheet with excellent deep drawability and excellent anti-aging properties, and manufacturing method. The cold rolled steel sheet comprises about C: above 0.015 to 0.150 wt %, Si: 1.0 wt % or less, Mn: 0.01 to 1.50 wt %, P: 0.10 wt % or less, S: 0.003 to 0.050 wt %, Al: 0.001 to below 0.010 wt %, N: 0.0001 to 0.0050 wt %, Ti: 0.001 wt % or more and Ti(wt %)/[1.5.times.S(wt %)+3.4.times.N(wt %)].ltoreq.about 1.0 and B: about 0.0001 to 0.0050 wt %, during annealing, grain growth is improved; Ti is added to form a nitride and a sulfide to avoid precipitation of fine TiC; B is added to precipitate Boron precipitates (Fe.sub.2 B, Fex(C,B)y) in a cooling the hot rolled steel sheet and in cooling step during annealing after cold rolling; a spherical cementite is precipitated and grown in which the Boron series precipitate is a precipitation site.

Cold rolled steel sheet and method of making

In a non-oriented electromagnetic steel sheet including about 0.01 wt % or less of C, about 1.0 wt % or less of Si, Mn in a range of about 0.1 wt % to 1.5 wt %, Al in a range of about 0.2 wt % to 1.5 wt %; the steel sheet having a critical amount of about 2 to 80 ppm rare earth metal, and the quantities of Ti and Zr in the steel sheet being limited to about 15 ppm or less of Ti, and about 80 ppm or less of Zr. The sheet exhibits excellent magnetic characteristics, such as iron loss, even when punched and laminated sheets are stress relief annealed at a low temperature for a short period of time.

Non-oriented electromagnetic steel sheet with low iron loss after stress

Hot rolled steel sheets and method of producing the same

This invention relates to a non-oriented electromagnetic steel sheet with low leakage flux for a compact transformer and a method for making the same. After stress relief annealing, the magnetic permeability .mu..sub.C of the sheet in the direction transverse to the sheet rolling direction is

Low leakage flux, non-oriented electromagnetic steel sheet, and core and

A non-oriented silicon steel sheet having a low core loss contains Si in an amount of about 2.5-5.0 wt % and S restricted to about 0.003 wt % or less and inclusions; the volume ratio of those inclusions having a particle size of about 4 .mu.m or higher to the total volume of inclusions is about 5-60%, and the volume ratio of inclusions having a particle size less than about 1 .mu.m to the total volume of inclusions is about 1-15%; when the sheet contains Mn in an amount of about 0.4-1.5%, and the volume ratio of particles less than 1 .mu.m is about 1-5%, the silicon steel sheet also has a low rotation core loss. The method of manufacturing comprises controlling the change of a cooling speed to about 5.degree. C./s.sup.2 or less in the cooling process of such steel sheet in a finish annealing.

Non-oriented silicon steel sheet and method

A process is disclosed for the production of a non-oriented electromagnetic steel strip having its magnetic characteristics uniformly retained in the product coil. The process involves by full- or semi-processing, hot rolling a steel slab containing not more than about 0.03% by weight of C, not more than about 3% by weight of Si and not more than about 2% by weight of Al such that the equation [Si wt %]+3 [Al wt %]-6 [C wt %] is in the range of about 0 to 2; and cold rolling the hot rolled steel strip in a known manner, followed optionally by finish annealing and also optionally by skin-pass rolling. The coil is finish rolled at a peripheral roll speed between about 500 to 1,500 mpm at the final stand. The peripheral roll speed at the final finish rolling stand is also controlled within a range of no more than about 300 mpm. Hot rolling is completed at a temperature Tf (.degree. C.) in an alpha-phase temperature zone and not less than about {750+30 ([Si wt %]+3 [Al wt %]-6 [C wt %])}.

Process for producing non-oriented electromagnetic steel strip capable

A method of producing a non-oriented electromagnetic steel strip by subjecting a low-carbon steel slab to hot-rolling, cold rolling at a small reduction and first annealing. In order to improve magnetic flux density and surface appearance of the product, specific conditions are employed so as to coarsen the crystalline structure to obtain a controlled and moderate crystal grain size after the annealing. The slab is cold-rolled at a rolling reduction of about 5 to 15% and is subjected to first annealing by heating at a rate of about 3.degree. C./sec or higher and holding the strip for about 5 to 30 seconds at 850.degree. C. to the A.sub.3 transformation temperature of the steel, while controlling the crystal grain size to about 100 to 200 .mu.m after first annealing.

Method of producing non-oriented electromagnetic steel strip having

Method of producing grain oriented silicon steel sheets having improved

An extra-low carbon cold rolled steel sheet useful for use in automobiles and the like, having an improved spot weldability is obtained by combining and adding Ti, Nb and B in predetermined amounts to an extra-low carbon steel to control the amount of fine Ti precipitate dispersed in steel to within a specified reasonable range. Furthermore, the spot weldability is improved by controlling the production conditions of the extra-low carbon steel sheet to within specified reasonable ranges.

Cold rolled steel sheets having improved spot weldability

An extra-low carbon cold rolled steel sheet useful for use in automobiles, and the like, having an improved spot weldability is obtained by combining and adding Ti, Nb and B in predetermined amounts to the extra-low carbon steel to control the amount of fine Ti precipitate dispersed in steel to within a specified reasonable range. Furthermore, the spot weldability is improved by controlling the production conditions of the extra-low carbon steel sheet to within specified reasonable ranges.

Method for producing cold rolled steel sheets having improved spot

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Chiba, Japan

Takashi Obara